• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.292-299
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• 2012

This paper proposes the design of circularly polarized multi band antenna for a non-linear junction detector (NLJD) system. In order to design for broad bandwidth, the CPW (Co-Planar Waveguide) feeding method is considered in this design. In order to realize the circular polarization, the axial ratio was controlled by inserting a $45^{\circ}$ inclined slot on radiating element and by cutting an edge of the radiating patch. Measurement results of return loss, bandwidth, axial ratio, polarization pattern and gain are agreed well with their simulation results in interested frequency band at 2.4~ 2.44 GHz, 4.84~4.92 GHz, and 7.28~7.32 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.4
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• pp.357-365
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• 2013

The 4 by 4 series slot sub-array antenna is proposed using substrate integrated waveguide(SIW) technology for 35 GHz of Ka band application. The proposed antenna is realized with multi-layered structure for compact size and easy integration features. 4 by 4 radiating slots are arrayed on top PCB with equal spacing and the feeding SIWs are arranged on middle and bottom PCBs for uniform power distribution. The multi-layered antenna is realized using RT/Duroid 5880 that has dielectric constant of 2.2 and the total antenna size is $750.76mm^2$. The individual parts such as radiators and feeding networks are simulated using full-wave simulator CST MWS. Furthermore, the total sub-array antenna also fabricated and measured the electrical performances such as impedance bandwidth under the criteria of -10 dB(490 MHz), maximum gain(18.02 dBi), sidelobe level(SLL)(-11.0 dB), and cross polarization discrimination (XPD)(-20.16 dB).